VCAST: An Infrastructure-Less Vehicular Traffic Information Service With Distance-Sensitive Precision

In this paper, the authors describe VCAST, an algorithm for obtaining individual vehicle location as well as aggregate traffic information over an infrastructure-less multi-hop wireless vehicular network. VCAST can be used to improve safety against collisions, inform about approaching emergency vehicles and lane merging vehicles (that may even be beyond a single hop communication range) and to enable dynamic routing and navigation techniques by providing aggregate traffic information in an extended neighborhood. To ensure scalability in forwarding information over multiple hops, they exploit a notion of distance sensitivity in information propagation, by which traffic information is propagated at a rate that decreases linearly with distance from the source.